A gas turbine includes a compressor, a combustor and a turbine. The compressor compresses the air from an air inlet so that the air becomes a high temperature and pressure compressed air. The combustor burns the compressed air with supplying fuel. The high temperature and pressure combustion gas drives the turbine and also drives an electricity generator connected to the turbine. In such a case, the turbine includes a plurality of turbine vanes and turbine blades that are alternately provided in a cylinder. Driving the turbine blades with the combustion gas rotates and drives an output shaft to which the electricity generator is connected. The energy of the combustion gas (flue gas) after driving the turbine is gradually converted into pressure with a flue gas diffuser without loss and is released into the air.
The flue gas diffuser is provided at the turbine in the gas turbine having such a configuration so as to extend the flow passage area from the exit of the turbine, namely, the entrance of the diffuser in the direction in which the flue gas fluidizes. The flue gas diffuser decelerates the flue gas after the power is recovered in the turbine and can restore the pressure.
A gas turbine having such a flue gas diffuser is, for example, described in Patent Literature 1.